Bascule-bridge



Oct. 20, 1931. P. E. STEVENS 1 ,827,9

I BASCULE BRIDGE Filed Sept. 20, 1927 2 Sheets-Sheet 1 ATTORNEYS Oct. 20, 1931. P. E. STEVENS BASCULE BRIDGE Fi led Sept. 20, 1927 2 Sheets-Sheet 2 INVENTOR M ATTORNEYS Patented Oct. 20, i V

Q i Q Q i BER-LILY ErsTEvENs, on QI-IICAGQfILL'iNOIS, ASSiGNOR orpNn rHiRni To; SYLVAN-,'E.-.

-HEssANn.ometrnrnnmo tnoronn rrsrnme,BotrH 'oF-smrAUt, MINNESOTA BASGU-LEHBRIDGE UApplicationfi1e d September 20, 1927.J=1'Se1ia1;;1 ]0.-2205677. H

invention relates to aI nevv, a-nd;: im- .provedbridge of thebascule type. 1

[g Oneof.the' objeots of my inventi'ouis t improve baseule bridges so that they can. be raisedinto the vertical position with a .VIIIIHII- nuinof effortv and expense. 7

ADOtl16I':Ob]6Ct of. my invention. is tov devise a type o-fbascule bridge Whiohf'can be made.

of considerable length and vveightland Whieh oan be. verylreadily manipulated ,and with a. minimum. expenditure of energy.

Anotherobject ofmy invention is toprog H p, p U type requires very. heavyjeountervieightsand vide a .bas'cule bridge which. can be raised so asto clear the stream or body. ofWater over whichiit is normally located in. a horizontal .po'sition, .While the .center of gravity of (the bridge is either notlraised at all or is. raised toa. very slight degree.

j Lnotherobjectof myinventionistoprogo vide a..bascule bridge .Which..,shall require :less steel for a giyenspan and.v eap'acity and .whiehcanubegnian faetured at adower post than typesinow' in use.

- Cther objeetsfoflmy invention.dvilhbeset 'forth in. the following. description andfdraw k .ings Which. illustratea preferredembodiment 1 thereof, it beingv understood thatthelabove f generalstatement oftheobj ects of my. invention is intended merely. to generally explain 1 30 the .sameand. not.to;limit it in any manner.

,Fig. 1 isi a diagrammatic ,draivvingi whieh illustrates. the geometric principle involyed. Fig, 2 is a'drawing similar to Fig. l. --Fig.f 3..is a diagrammatic side elevation of $35 my improved..briclge.

' "Fig; A. is anend' view. I

Fig: {5. is another. diagrammatic side elevation. of iii-y; improved bridge, shovvinga' diff--- ferentembodiment. I V ;-;-4o Figs 6iis1anend .vieW .of Eig; 5.

. oule bridges have. been. generally. used; I Pfl'lllie first. pr simply balanced :t-runnion type: has

counterweight directlyattached .to' a shore.

a pivotpor-trunnion flfThis;typerequires a I I i the line A Bhas a fixed length andthe-point v is moved towards the origin .Oalong-the I horizontal line X X, so thatthe point B will 1 00 eou nte riveight several times ,as hea-vy as the span itself and so located that a straight-line 5 pa'ssing through the centero fgrayityot the Y'stru'cture. p "In Ithel second type, namely, the, so-elalled o'iten very objectionable.

I ftllid limited.

Heretofore, three Z prineipal types .of has-- spanand also assing. through the. trunnion fv'vill; pass through .'the .eenter of of the eounterwei'ght. 'ltis avery .ineo'nvenient and sometlmes impossible .to. .ut1li ze such, af 7 resume. type, one end of the span is :sup-

ported upona trunnion, a. eounterweight is supported on one end of a. ;trussed'lever,and the other end of the lever is coupled lfwithggq the span so that the,span and the'le'verjmove up.. or down ,in. .parallelvmiotion. 'f -l. This. second supporting structures and forlthis reason is 355 .The .thlrd 0r tfS cherZ er? type. compr ses 7 a span. hav ng a shore ,QXtGIlSlOIL formed like Ithesegment. of. a.wheell and. thlS CQlI Il t/I" eighted to bringjthecenter oflgravityof the entire: structure to the geometric center zoff 7' thewheel, segment softhat vvhen: the gspamis it rolls along atra-ck on theshore. R 'Ihisiithird type also frequiresfvery' heavy counterweights. and v supporting .struetures' ",According to my inventiomthelstructure .is sov devised that the commonoenter oltgravity of the moving parts travels to or from the shore along a horizontatline so thatftric-ggso tion is the. only force to be overeome by; the

. Qperating mechanism. In manyeases my improved bridge can. be inadeentirelymvithoiit i eountervveightsg and .YVllQI'G eounteryveights V are employed, they ean be made much lighter than in the knovvn types ofbascule This effects a very substantial ee'on omy c ost loffconstructioniand .operation. 7

. 'ConsideringfFig. 1, for examplefifutiie re di t t e be anoh ter tatth origin 0 and if a third line A Bis'draw nj in Will-,be of equal length. If it'isassumedithat i .te-Jemeehere .ii eeeed be moved downwardly on the axis Y'Y, then the point C will trace the are C of a circle, the center of said circle being at O and said circle having a radius 0 C, said radius being equal to A C and to B C.

Conversely, if we assume link of fixed length equalto A G and B C,

and that thepoint B is then moved along the vertical axis Y Y, then the point A will move along the horizontal axis X- If we assume that the point A is the cen ter of gravity ofa movable span, that the point C is a pivot conveniently located on the span, and that the point 0 is a pivoton supporting structure of the span (itbeing'as'sumed that the'points'A and G are "on" the same horizontal line) and that the po1nt B is a point on the span which 1s plvoted to a carriage running on a vertical track,

' then if the points 0 and G are connected by p "a link of fixed length, the entire structure porting 'movealong the line'D O (prolonged) and if tion. Referring again to Fig. 2, if the point E on maybe moved without overcoming any force except friction, because the center of gravity A moves wholly along a horizontal hne. j

. As shown in Fig. 2, since the lines AC,

B C and O C are all of the same length, a com- 1 plete circle 0 may be drawn aboutthe point C as a center, sov that said circle C will pass through the points A B and O.

If we'assume that this circle O? is part of a movable, structure of which the line A B :is also apart, and the structure is moved so "that thepoint A (the center of gravity of the span) moves along a horizontal line, while the point B moves along a vertical line andthe point 0 moves along the are C previousdly'rnentioned, then each point on. the circumference ofthe circle C Wlll travel along a straightline passing through the origin O.

.For example, the point E on the circle willmovealong the line E O which is prolonged beyond the origin 0, and the point D will move along the line D Owhich is similarly prolonged. I

It is clear that if the point D on the movable structure is guided by a track on the supstructure so that it is compelled to the point C on the movable structure is conne cted to the point 0 of the supporting structurebythelink O C of fixed length, that the point A on the moving structure will travel along the horizontal axis X X so that again the onlyresistance to be overcome by the operating mechanism will be that or" fricp 7 that the point C is connected to the origin 0 by means ofa' E O. The center of gravity A will travel along the horizontal line X X.

In the bridge diagrammatically illustrated in Figs. 3 and A, the operation is that illustratec'l in Fig. 2, it being assumed that the link O C is utilized. The span B is provided with piers P and P of any suitable type. The pier P serves to support the free end of the span when said span-is in the horizontal position. The link GC is pivotally connected at O to the pier P. Likewise, the mechanism for upwardly tilting the span B is connected to pier P. However, the heel of the span B is not directly connected to pier P, save through the link 06.

In Fig. 3 the centre of gravity of the span 8 is located at point A when the, span is closed and just behind point when the span is fully raised. The point D of the circle C shown in Fig. 2, which represents a point on the heel of the span, is pivotally connected .to a carriage F which is compelled to move along a track G parallel to the line D 0, sothat the point D moves along the lineD O prolonged, while the span is free to tilt with respect to carriage F. The point D is moved to the point D and back so that the bridge swings back and forth through an angle of 75. The upper position of the bridge is shown in dotted lines in Fig. 3. As shown by this dotted line position, the span can tilt with respect to carriage F.

The device shown in Figs. 5 and 6 corre--- sponds to the embodiment of Fig. 2 with the link OG eliminated and with two tracks for guiding the movement of the points D and E. The center of gravity of the span is again designated by the point A. The imaginary circle C is the same as before. The point D again represents a pivotal connection between the heel of the span and a carriage which movesup and down along the track G so that the point D can move to the point D along a line parallel to the track G.

Likewise, the point E of the span is a pivotal' connection between the heel of the span and a carriage which moves along a track G so thatthe point E can move to the point E along a line parallel to the said track. The lines of movement of the points E and D pass through the point O. Asshown by the'dotted line position in Fig. 5, the span can tilt with flespect to the carriages associated with its ee o g i The embodiment shown in Figs. 3 and 4 illustrates the application of my device to a {highwaybridge over a canal lock, andthe embodiment of Figs. 5 and 6 illustrates the application ofmy device to a typical railroad crossing. I

In theembodiment shown in Figs. 3 and 4: the span will be in stable equilibrium in all positions. The operating force may be ap-' plied to the link 0 C or by means of the well known-operating strut attached to any convenient poi-ntiofthe an. Any suitable =lo ck ing; device {may be provided for-the righthand endofthe spa-n an'dgenerallyspeaking, Well knewn accessonies imay be utilized. 1: p 7

5 -The device-showniin Fi-gs. tent 6 may require a counterweight to shift the center of a gravity of the span trom the point-G =to the point A. However;thiscounterweight ---needonly have the weight of about 200,000 lbs. Whereas counterweight I applied -t to a 2 bridge 'of'ordinaryvdesign has aflveight of -The carriage q wh' h guidesuthefi movement of -the point :E inJF-igs. fraud 6- may be" ex- 1 tended upwardly and the A weight may be so loeated'that it will; not descend below the t ==level=othetlecls ofrthe' bridge. 'The-lineG -E:in FigJSis nIy indicated toishOwtthe-re- -lation between tthe: Weight of: the structure, r v r2 the counterweight .and :the common" centerof gravity A. p t L "Thespan shown'in Figsxoand 6;.1nay be cenveniently top'erated by; a a driving mechannism connected to 2:tl1e::earriage associated 15125 1 with the point 1 E. or..by the 1 familiar; operataidngstrut. ."Lockin gcme chanism may beprovidedeat theipoint D. I

. 1 The counterweightaieed not: be necessarily ,-.located=atE;nor even on: the circle 0?; if the v s:;;30 .-counterweight:isnot located onthe circle C 5 preterable to carryit directly upon the frame of the moving span.

The-locationiofAimay) be: varied by varytie- :3 :thea-positioni and the-weight of the coun- :terweight.

The point-A having-been determined by the POS'itlOIIjaIICl weight, .of-the-counterweight, the 1 i center L. C gofzthe circleaC ;in- Fig; 5 may be "C because my "invention covers a construe- 'tionin which one or both o'f s aidgpointsare spacedtrom s'aidcircleO i': J p I I (Of course, ifithe' pointsl) and E or'either of 'themjare not von the circle C then: these points move in, curved lines when the; bridge mined by the engineer by ffirstfixing the poutilizing said circle and zthe vvcenter thereof asthe mathematical control for determining support -,forthe span.

the path: of any point selected as a Q'point of -tocounterbalancethese forces and to produce t ME I t Asnitablecurved trackortracksinay be placedein anyione ofga large variety ofposi-Q tions nelativezto A; 'The'point O is prefer.

sitionof-thecircle (Rand of itscenter C and utilized for guiding the movement of points off the circle C I v The structural: frame illustrated inlthe drawings is merely diagrammatic as 1 these -deta1lsmaybe varied'faccordlng to standard engineering'practica p It 'vill be: noted that in both embodiments Lot my invention; the point G-which is be- -low the center of gravityA and which is oliiset from said point Ain the directionlot movement of:theflspan,is caused 'to move downwardly and also 7 in said direction :of

movementjofthe span, it being preferably compelledito move in a circular path while the point A moves along a substantially hori- --z ontal= path. f

1 "it will also be noted,

upon considering 2,1that two of the points of the span, namely,

vertical linerY Y." If the paths or" movement ofthe points D and E. are straight lines; then saidSpathsintersectv at the point Owvhichr-is f substantiallyat the'tlevel of the point-Al v I have shown v.a preferred embodiment o1 :my invention. but it clear that numerous changes: and omissions could be made :Without de aartingsfrom its spirit. 5

Since the line 6G is drawn "to the middle wit-twillrmoveeinv. akcu-rveaand=it'isftherefore p nt fr hegline ABgithe'n if'the line AL is the points E and D are caused'to move along vpaths whichare lnchnedato each other and which are.on*oppos1tesides ofthe common drawn 'parallel' to: the vertical, axisand 2 he i p line BL. is; drawn parallel to the horizontal axis arelctangle is'formedofwhich thef'line ABztornis one diagonaland'the line 056 forms one-halt ot'ithei other diagonal. Assume that the point A is releasedfrom the horizon al lineorthe track t represented by XXV so that the tilting movement of the span v whose center of gravityas represented by: A, is guided "by the movenient of the nointB- along a vertical track l and by the supplemental guide provided the link 00, For con enience, the point B maybe designated as the lower point,since 2 it is furthest below the'center. of gravity A, and-the point C may-be called the Fupper point, since-it is above the point B. 7 Like- W188, forconvenience the gulde means for the point Br-inay be designated as the primary 'guid'e; .means, and the guide means for-the mental guide means.

point C,- in the counter-clockwise direction;

point G*may be designated as the supple- Assumingithatfthe point A is no longer loca ed upon a horizontal track, equilib.-' i'rium must be secured by'balancing the force I A p p V I p 10f gravity. v Assume that the force'of gravity 'israised. These curves can be read1lydeter- Since. the verticaltrack YY is rigid y/there action thereof produces 'a 'force which can be representedlbythevector line BL. In order fiqlllllbl lumfEhlGaCtlOn must be created by-the' tension produced on the link OC, and this third force can be represented by the vector line LO. If the link did not have the inclination and position diagrammatlcally shown in Fig 1, then the reaction thereof would not produce equilibriuin rIence the force of gravity is counterbalanced, by producinga horizontal forceupon the lower point which is directed towards the vertical gravity.

In the embodiment diagrammatically illustrated in Fig. 2, in which the sliding point D, and the'link OC are utilized, the point D corresponds to and is equivalent to the point B, and it can be readily shown that the same equilibrium is produced, it the center of gravity A is free. In this case the reaction of the inclined track along which the point D slides produces a force having a horizontal component directed towards the vertical line passing through the center of gravity.

Likewise, in the embodiment diagrammatically shown in Fig. 2, in which the link CC is eliminated, the reaction of the track along which the point D slides, produces a horizontal force directed towards the vertical line. passing through the center of gravity A and an upwardly directed vertical force. The reaction of the track along which the point E slides, also produces an upwardly directed vertical force and inaddition,a

is one in which such equilibrium is produced, it would not .be departing from ,my inven- 7 tion it such equilibrium was not attained, as long as it was substantially attained. For

the purposes of my invention, such equilibrium is substantially obtained it it is possible to use a counterweight which has less,

weight than those necessary in previous designs, which have been generally mentioned in theprevious part of this description.

I claim:' 1 V V 1. In combination with a bascule bridge having a movable span, a first guide means adapted to continuously cooperate with a first predetermined portion 7 of said span which is behind the center of gravity thereof, and second guide means adapted to continu- V ously cooperate with a second predetermined portion of said'span which is also behind the center of gravity thereof, the force of gravity acting upon said span being adapted to continuously downwardly stress both said guide means, one of "the guide means being so shaped that the reactive stress thus produced is at-all parts thereof a force havingan upwardly directed component andfalso having ,10 a horizontal component directed away from a vertical 3 line passing through the center of gravity of the span. 7

2. In combination with the movable span of a bascule bridge, guide means associated '75 with two separated points of the rear portion of said span, said guide means being shaped to cause the movement of a third point of said span which is substantially equidistant from said separated points,in a substantially circular path, whenthe span is upwardly tilted, saidthird point moving in said path in a direction away from the vertical line whichpasses through the center of gravity of the span whent-he span is hori-" s5 zontal.

3. In combination with the movable span of a bascule bridge, a track adapted-toslidably guide the movement of a point on the heel portion of the span, when the span is' '90 tilted, and a linkv pivotally connected at one end to a support and. pivotally connected at its other end to a second point on said span whose level is higher than the level of the firstanentioned point of the span, said'sec es ond point being between the first-mentioned point of the spanand the center of gravity thereof. I r

4. In-combination with the movable span 7 of a bascule bridge, a track adapted to slid-" ably guide the movement of a point on the heel portion of the span, when the span is tilted, and a link pivotally connected at one end to a support and pivotally connected at its other end to a second point on said span whose level is higher than the level of the first-mentioned point of the span, said second point being between the first-mentioned point ofthe span and the center of gravity thereof, thedistance between said first-men-" hlO tionecl point and the second point of the span beingsubstantially equal to the, length of saidlinle' q 5. In combination with the movable span of a bascule bridge, a pair'of tracks inclined to each other andcoppositely inclined to a vertical line, and means adapted to guide a pair of points of the rear portion of said span along said tracks, one of said points.

being above and the other of said points being below the centerof gravity of the span.

6. In combination with the movable span of a bascule bridge, a pair of tracks inclined to each other and oppositely inclined to a verticalline, and means adapted to guide 63125 pair of points of the rear portion ofsaid span along said tracks, 0119,01? said points being above and the other of said points being below the center-of gravity of the span,said tracks being straight and having their lines of direction parallel to lines which. cross each other at a point located on a circle which passes through four-points, namely, the center of gravity of the span, the said two points of the span, and said point of crossing.

7. In combination with the movable span of a bascule bridge, a fixed shore support, an inclined track extending towards the channel.

of the span, a link which is downwardly inclined when said span is in the horizontal position, the upper end of-said link being pivotally connected to a fixedpoint on said'support, the lower end of said link being con nected to a point behind and below the centre of gravity of the span when it is in said horizontal position, said span also having a sliding connection with said trackwhich is continuously below the lower end of said link.

In testimony to r whereof I affix my signature.

PERLEY E. STEVENS. 

